/Engine/Source/Editor/Kismet/Public/BlueprintEditor.h
virtual void OnActiveTabChanged ( [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [SDockTab](API\Runtime\Slate\Widgets\Docking\SDockTab) > PreviouslyActive, [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [SDockTab](API\Runtime\Slate\Widgets\Docking\SDockTab) > NewlyActivated )